W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://nvidia.github.io/libnvidia-container/ubuntu16.04/amd64  InRelease: The following signatures were invalid: KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://nvidia.github.io/nvidia-container-runtime/ubuntu16.04/amd64  InRelease: The following signatures were invalid: KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://nvidia.github.io/nvidia-docker/ubuntu16.04/amd64  InRelease: The following signatures were invalid: KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745
W: GPG error: http://ppa.launchpad.net/kivy-team/kivy/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A94F2C37A863D2D6
W: The repository 'http://ppa.launchpad.net/kivy-team/kivy/ubuntu xenial InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://ppa.launchpad.net/openjdk-r/ppa/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EB9B1D8886F44E2A
W: The repository 'http://ppa.launchpad.net/openjdk-r/ppa/ubuntu xenial InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: Failed to fetch https://nvidia.github.io/libnvidia-container/ubuntu16.04/amd64/InRelease  The following signatures were invalid: KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745
W: Failed to fetch https://nvidia.github.io/nvidia-container-runtime/ubuntu16.04/amd64/InRelease  The following signatures were invalid: KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745
W: Failed to fetch https://nvidia.github.io/nvidia-docker/ubuntu16.04/amd64/InRelease  The following signatures were invalid: KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745  KEYEXPIRED 1538166745
W: Some index files failed to download. They have been ignored, or old ones used instead.